Journal of Resources and Ecology ›› 2012, Vol. 3 ›› Issue (1): 93-96.DOI: 10.5814/j.issn.1674-764x.2012.01.014

• Reports • Previous Articles    

Quantifying of Soil Denitrification Potential in a Wetland Ecosystem, Ochi Experiment Site, Japan

ZHANG Qiuying1,3, LI Fadong2, TANG Changyuan3   

  1. 1. Key Laboratory of Agricultural Water Resources, Centre for Agricultural Resources Research, Institute of Genetic and Developmental Biology, CAS, Shijiazhuang 050021, China;
    2. Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    3. Faculty of Horticulture, Chiba University, Chiba 271-8510, Japan
  • Received:2012-02-05 Revised:2012-03-01 Online:2012-03-30 Published:2012-03-30
  • Supported by:

    This study was supported by the 100-Talent Project, Chinese Academy of Sciences and the Grant-in-Aid for Scientific Research of Japan Society for the Promotion of Science (No. 19310004).

Abstract: Nitrate contamination has become one of the most important issues for surface water and groundwater. N2O, with an increasing contribution to global warming, has been more and more attention by the IPCC recently. As well known, denitrification plays a major role in nitrogen cycle of aquatic ecosystems and operates at rates far below its potential under proper conditions. Sediments are the single largest pool of nitrogen in wetland ecosystems. During this process, facultative anaerobic bacteria transform nitrite into nitrogen gas which dissolves in the groundwater and diffuses into the atmosphere finally when it shows up with seepage or spring in the wetland. To seek a mechanistic understanding of N removal in natural wetland ecosystem, a case study was carried in terms of denitrification rate at the Ochi catchment, Chiba, Japan. In this study, samples of intact soil cores in 0–20cm were taken along the groundwater flow path, which including 2 samples in the unsaturated zone and 2 in saturated wetland ecosystem. Denitrification capacity of soil was quantified using acetylene (C2H2) inhibition/gas chromatography ECD method with time intervals of 0, 2, 6, 12, 24 h. Total-N and Total-C contents and amount of denitrifying bacteria were also analyzed. It is found that denitrification ability is low for all 2 samples in the unsaturated zone and high in saturated zone. Results show that N2O emission flux after C2H2-inhibition ranges from 0 to 1.17 gN m-2h-1, with an increase value prior 6 hours and slow down after that.

Key words: denitrification, N2O emission, natural wetland